The invention relates to electronic sensors, and more particularly to protection of the terminals and wires on electronic sensors.
Electronic sensors, and more particularly, variable reluctance sensors are well known and used in automotive applications such as brake systems, cruise control systems, transmission systems, as well as others. In general, variable reluctance sensors include a bobbin or spool assembly having a non-metal spool which houses magnetic elements and magnet wire. The magnet wire is coiled about a barrel portion of the spool. The end wires of the magnet wire are wrapped around terminal legs for electrical output to an external circuit. The spool assembly is then encapsulated within a metal or plastic housing. The encapsulating process includes sealing the magnetic elements and magnet wire from liquid intrusion, so that the variable reluctance sensor is protected in its environment on the vehicle from corrosive liquids, splash, spill, or other debris. During the encapsulating process, a cap is slid over the spool assembly and the end wires wound around the terminal legs. As the cap slides over the end wires, the wires may be inadvertently damaged or scuffed by the moving cap. A damaged magnet wire can result in an xe2x80x9copen circuitxe2x80x9d failure condition. Variable reluctance sensors are required to have a reliability and a design life to match warranty target periods of 100,000 to 200,000 miles of the associated vehicle. Failure of the variable reluctance sensor may result in poor engine performance of the vehicle. Consequently, there is a need for designing the variable reluctance sensor, and especially the terminal of the variable reluctance sensor so that the end wires are not damaged upon installation of the cap.
The invention is an improvement to an electronic sensor having a spool assembly. The spool assembly includes a spool with a cavity therein for receiving a pole piece and a magnet adjacent the pole piece. A magnet wire is coiled around the spool. Each end of the magnet wire is coiled around a respective electrical conductive terminal leg for electrical output from the coil to an external circuit. A cap slides over the spool assembly and the terminal legs for sealing the components from liquid and debris. The improvement to the electronic sensor includes bumps or protuberances stamped onto the terminal legs. The bumps or protuberances have a height greater than the diameter of the wire or bundle of wires coiled around the terminal leg.
Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.